BU-804c: Water Loss, Acid Stratification and Surface Charge

During use, and especially on overcharge, the water in the electrolyte splits into hydrogen and oxygen. The battery begins to gas, which results in water loss. In flooded batteries, water can be added but in sealed batteries, water loss leads to an eventual dry-out and decline in capacity. Water loss from a sealed unit can eventually cause disintegration of the separator. The initial stages of dry-out can go undetected and a drop in capacity may not be immediately evident. Early detection of this failure is important. Read about Charging Lead Acid, under Watering.

On overcharge, a battery becomes a “water-splitting device” that turns water into oxygen and hydrogen. A parallel can be made with the fuel cell, but this device does the opposite; it turns oxygen and hydrogen back to electricity and produces water. Turning water into hydrogen needs energy and in a battery this is in the form of overcharge. Converting hydrogen and oxygen back to water regenerates energy. Read about the Fuel Cell.

Acid Stratification

The electrolyte of a stratified battery concentrates at the bottom, starving the upper half of the cell. Acid stratification occurs if the battery dwells at low charge (below 80 percent), never receives a full charge and has shallow discharges. Driving a car for short distances with power-robbing accessories contributes to acid stratification because the alternator cannot always apply a saturated charge. Large luxury cars are especially prone to acid stratification. This is not a battery defect per se but the result of use. Figure 1 illustrates a normal battery in which the acid is equally distributed from top to bottom.

Normal battery


Figure 1: Normal battery

The acid is equally distributed from the top to the bottom of the battery, providing good overall performance.

Courtesy of Cadex

Figure 2 shows a stratified battery in which the acid concentration is light on top and heavy on the bottom. The light acid on top limits plate activation, promotes corrosion and reduces the performance, while the high acid concentration on the bottom makes the battery appear more charged than it is and artificially raises the open-circuit voltage. Because of unequal charge across the plates, CCA performance, or the ability to crank the engine, is also reduced.

Stratified battery

Figure 2: Stratified battery

The acid concentration is light on top and heavy on the bottom. This raises the open circuit voltage and the battery appears fully charged. Excessive acid concentration induces sulfation on the lower half of the plates.

Courtesy of Cadex

Allowing the battery to rest for a few days, doing a shaking motion or tipping the battery on its side helps correct the problem. Applying an equalizing charge by raising the voltage of a 12-volt battery to 16 volts for one to two hours also helps by mixing the electrolyte through electrolysis. Avoid extending the topping charge beyond its recommended time.

Acid stratification cannot always be avoided. During cold winter months, starter batteries of most passenger cars dwell at a 75 percent charge level. Knowing that motor idling and driving in gridlocked traffic does not sufficiently charge the battery, a charge with an external charger may be needed from time to time. If this is not practical, switch to an AGM battery [See BU-201a, Absorbent Glass Mat (AGM)]. AGM does not suffer from acid stratification and is less subject to sulfation if undercharged than is the case with the flooded version. AGM is a little more expensive than the flooded starter battery but tends to last longer.

Surface Charge

Lead acid batteries are sluggish and cannot convert lead sulfate to lead and lead dioxide quickly enough during charge. As a result, most of the charge activities occur on the plate surfaces. This induces a higher state-of-charge on the outside than in the inner plate. A battery with surface charge has a slightly elevated voltage. To normalize the condition, switch on electrical loads to remove about one percent of the battery’s capacity, or allow the battery to rest for a few hours. Surface charge is not a battery defect but a reversible condition resulting from charging.

Simple Guidelines for Extending Battery Life

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On March 8, 2012 at 9:09pm
Eamon wrote:

I think that should be “use distilled or DEionized water”

On March 8, 2012 at 11:59pm
Bevan Paynter wrote:

If one has knowledge of water treatment technology as I do, one would know that rain water at about 20ppm will do- I use without adverse effects. As will melted ice water from fridge/freezer-even better. As comparison, distilled water is about 5ppm, de-ionized about same- tap water depending on source may have from 300- 2000 pm- TDS-(total dissolved solids or salts) -definitely harmful to batts & car /vehicle radiators! Also steam irons! A TDS meter measures level in sample- without one, simply use a multimeter on Ohms with probes dipped into sample- the higher the reading the better-i,e, infinity- drop a pinch of salt into sample & watch reading lower!

On March 27, 2012 at 10:36am
Bill the Fisherman with Deep Cycle Saddness wrote:

I added too much water to a lead acid battery and it performs poorly now.

Can i simply remove water and lower the level to just above the plates to restore battery performance ?

Or should remove water and add electrolyte solution ?

Is there a test kit for the proper electrolyte to water mixture ?

Is the specific gravity the result of the electrolyte and water mixture ?

Any info on test kits or fixing this self induced problem is greatly appreciated.

On March 27, 2012 at 11:23pm
Bevan Paynter wrote:

Much depends on type of batt & age of batt- on the face of it, adding slightly too much water should not matter much. The specific gravity of a batt is measured commonly by a hydrometer-cheaply available. The sg is highest when batt fully charged-ie all acid is in the electrolyte solution. I wonder why you had to add lots of water- thinking your batt may be worn out- or is your charging system over-charging? Even the best batts have a certain service life-ie no of charge-discharge, depth of discharge, sitting discharged- etc-etc-etc-all covered on this site. Fully charge batt- don,t overcharge. Measure sg. If low, could be sulfation, or you have lost acid by overfilling- spilling electrolyte. If so, you could try emptying electrolyte out of batt & refilling with new electrolyte- sg depending on type of batt.-eg starter batt=1.260- deep cycle- 1.220 @ 20’C. Look for crack or split in casing of batt- losing electrolyte. So there you are- if you can,t work it out from all the info on this site- we give up!.

On May 6, 2012 at 4:43pm
peter wrote:

Bevan, we have installed a lead-acid battery bank on a solar system 4 years ago. The system Voltage is 48 V and the batteries bank consist of 24 x 2 V batteries. Recently we noticed that some of the batteries have “cracked”. What could be the reason for this?

On May 6, 2012 at 11:54pm
Bevan Paynter wrote:

Peter- please say what “cracked” means- are the casings cracked & leaking electrolyte? Are the casings clear see thru polycarbonate? Are the casings bulging out-ie-swollen? If so- likely to be sulphation-also plates will have white coating if so. Sulphation is always caused by batts being undercharged & left that way. It is difficult to remove once there. I take it batt-ie each cell -has proper electrolyte level, o/c volts are ok, connector straps are making good contact? Unfortunately, RAPS once installed are usually ignored till trouble arises! The other thing all else being well is vibration or freezing temps, or even lightning strike!.

On May 10, 2012 at 10:17pm
Ron Johnson wrote:

What causes the white powder the accumulates on (usually) the negative electrode?  What can one do about it?

On May 11, 2012 at 11:36pm
Bevan Paynter wrote:

The white or grey coating on neg/pos terminals is caused by electrolyte vapour from inside batt condensing on metal ext parts- to stop, clean conn, refit securely, & apply a coating to ext metal conns- pet jelly, or hi-melt grease, or even an oil film. There are even commercial products that do the same thing-ie, insulate the terms/conn from the SO2 corrosion.

On July 5, 2012 at 10:49pm
Random guy with problems wrote:

I got 2 small lead acid batteries at a goodwill store, and neither works.  How can I tell what the problem is? I tried refilling one (12v, 3ah) with filtered and boiled water, but it did nothing.  What should I do, and if needed, where can I get electrolyte solution?

On August 19, 2012 at 1:59pm
Bill in DC wrote:

I have a little, home-made standby power system consisting of nothing more than a float charger, a flooded, lead acid deep cycle battery and an inverter.  It has served me well through our frequent power-outages here and saves me hauling out the generator except when it is really needed.  A few weeks back, I noticed the battery making cooking noises just connected to the float charger.  Sure enough, the water level had gotten pretty low, uncovering maybe 30% of the plates even though the battery has probably only had about 30 cycles on it in the last three years.  I refilled with distilled water and am hoping for the best (but assume I am probably stuffed and am going to have to replace the battery now).  When a battery is barely used like this and just sits on a float charger continuously, how often do you need to check the water level?  As I now know, the answer is more frequently than “NEVER”, but how often do you need to do this for a battery which is barely used?    Thanks much!

On September 20, 2012 at 11:21pm
mike foster wrote:

purchased distilled water from walmart for the batteries in my golf cart, the acid turned red and all my batteries went dead to marginal , so I figured the charger got them, picked up distilled water from walmart again, this time I topped off the two batteries in my
sailboat, now they are dead. checked out the fine print on the walmart bottle,  the water is filtered and fed ozone, by a variety of means.
So much for the distilled water,

On November 12, 2012 at 12:01pm
Ben Ho wrote:

I have several large deep-cycle lead acid batteries (not sealed) that I used to run my boat’s electric outboard. I left them in storage for three years, and now just discovered that the batteries are practically dry with no liquid visible. Is it possible to revive them by adding distilled water?

On December 27, 2012 at 3:55am
Munya Dread wrote:

Bevan Paynter, thanks mate for the fridge water tip, i guess its got fewer dissolved salts than tap water will give it a try

On January 10, 2013 at 10:26am
corey wrote:

Is there a home made recipe to treat sulfation?

also as i read above,iam now scared to use distilled water,whats up with that

On January 10, 2013 at 12:44pm
Bill in DC wrote:

I have to say, I got one of those BatteryMinder things with desulfation.  It actually works if you can be patient with it.  The batteries looked horrible when I let the water get too low.  There was terrible sulfation on the parts of the battery above the water line and I was sure I was stuffed.  Sure enough it wouldn’t take a charge to 13v after I put it back on the charger once I added distilled water.  But I pushed this maintenance mode which pulses the battery periodically and just let it sit on that.  At first it seemed to have no effect, but I just left it.  It took about 8 weeks or so, but eventually I could charge it again.  I haven’t stress-tested the battery and am sure it isn’t 100% of what it was, but when I look down in the holes the white sulfation is now entirely gone and the plates look clean all the way down.  And it seems to have good voltage and holds a charge effectively again.  I am no expert in this, but I would definitely try this before pitching a battery, even one with very bad looking sulfation.  I am sure there is a point where too much is gone and you can’t recover it, but it cleans up even plates that looked doomed in my experience.

On April 9, 2013 at 2:24pm
Faraz wrote:

can a pluser make prolonged the lead acid battery life,and avoid sulfation.

On May 6, 2013 at 9:06am
dave wrote:

what will happen if i remove the electrolyte of the lead acid battery, then after 4 months refill again. what will happen to the battery and the effect?

On May 8, 2013 at 6:38am
lenny wrote:

followed,let me try it hoping for the best

On May 11, 2013 at 4:21am
Rafiqul wrote:

I use 12v lead acid deep cycle battery for domestic power backup.  Unfortunately the battery goes dry up about 80% and battery doesn’t backup farther.  What I’ll do now?

On May 17, 2013 at 2:49am
wilford wrote:

why should an accumulator not be placed directly on the ground but on an insulator?

On June 4, 2013 at 9:20am
hind wrote:

i wonder if companies are still using the flooded batteries (lead -antimony)??? batteries and why don’t switch to agm and valve regulated lead acid battery .

On June 12, 2013 at 9:27pm
Bob wrote:

I often ask my self the same questions,  with all these advances in technologies yet a battery design from 1860’s is still being used . Why not revolutionize capacitance and retire lead acid.  I am told there are still too many benefits to lead acid battery’s that others aren’t able to match as of yet.

On June 18, 2013 at 2:26am
Faraz wrote:

can a electronic digital pluser make prolonged the lead acid battery life and avoid sulfation by supplying electrical spikes (votage) to the battery.

On July 17, 2013 at 5:01pm
Kaz wrote:

If we have a sealed battery, can we drill a small fill hole in it to let gas escape, check the water level and top it off as necessary, and then seal the hole?

On July 18, 2013 at 1:07am
hussain wrote:

how much time required to for lead acid batteries to connect with charger after filling electrolyte

On August 5, 2013 at 10:53am
Stennis wrote:

I have an application using flooded lead-acid batteries where the equipment will be used 6 months of the year (two days a week) and then stored for 6 months. I have seen some battery chargers that do a short “boil” every so many hours (e.g. 21 hours) to suppress acid stratification.  Is this necessary, useful?.  If not, what can be done to extend the calendar lifetime of such a battery system.

The battery system is composed of 36 high Ah automotive starter batteries.  The large number of batteries is required for short high peak power levels (>150 kW) but DoD during operation is only 3-5% followed by immediate recharge.  Battery life is believed to be calendar limited and is a significant operating cost

On August 5, 2013 at 11:08pm
Bevan Paynter wrote:

Without knowing exact details i am guessing. But the longest lasting start batts are neither over charged nor under charged- quality of make is a big factor.SLA type batts for starter use have far lower self discharge. This acid stratification thing is only a factor in flooded batts that are always stationary. DOD could be important, as buckled plates could result. Really- seems as if this application has not been really thought out!(IMHO).

On August 6, 2013 at 2:33pm
Stennis wrote:


The application is a battery-electric winch for use in launching sailplanes (gliders, not hang gliders).  The batteries supply the peak power (~150 kW) while a much lower power (~6 -10 kW) portable generator (or ac mains) replenishes the batteries through chargers under the control of a systems controller.  This system is analogous to a series hybrid electric vehicle.  The energy extracted during a launch is on the order of 1.2 kWh over a period of about 45 seconds with the peak power occurring very early in the launch and the power tapering down smoothly from there to a much lower level (~25 kW) by the end of the launch..  Peak launch frequency might be 6 to 10 per hour with maybe 25 launch cycles in a day pretty busy.  The excess capacity in the batteries (36 72 Ah 12V starter batteries would hold be about 30 kWh) can be used to buffer the generator during peak launch periods after which the generator could catch back up.  Otherwise, the batteries are being very shallow cycled. 

In many applications, the winch would only be used weekends and it would be stored during the week.  In northern climes, operations commonly cease for up to 6 months during the winter.  During this period the winch would be parked in a hangar and there would be no physical motion to stir the batteries.  During these storage periods the system controller can command the chargers (via CANbus) to do whatever would be best to maximize the calendar life of the batteries, e.g. boil briefly to stir reducing stratification and/or counter self-discharge.

For prototype development, the battery system employed is expected to be flooded lead-acid as it is the least costly option and does not require sophisticated battery management.  There are already a number of high risk elements in this development and a complicated battery system does not serve the goal of demonstrating the value of the fundamental approach over current IC engine driven winches.  Longer term, it is expected that these winches will employ LiFePo or some other such energy storage systems, e.g. ultracapacitors, that can provide the high power density necessary with greatly reduced weight and increased durability.

The question is, over extended storage periods what can be done via the chargers, under control of the system controllers (which can sense individual battery - not cell - voltages), to maximize the lifetime of the flooded lead-acid batteries in the prototype.  If periodically stirring the batteries would be valuable, for how long and how often should this be done.

[For an example of such a launch using a classic internal combustion engine winch see

http://www.youtube.com/watch?v=UOp_EsplxDM ]

On August 6, 2013 at 10:44pm
Bevan Paynter wrote:

Stennis- I would completely go away from battery launch- there is nothing like ic engines for quality, longevity, energy delivery density- & let us not forget the well being of the pilot/s- there is just too much to go wrong with batteries!.

On August 7, 2013 at 8:49am
Stennis wrote:


I cannot disagree with you more on the value of electrically driven winches but this is not the forum for that discussion. Cost effective electrical energy storage is currently one of the more difficult issues with this concept but I believe it can be addressed in the longer term.  That is why for prototype work I am planning to use lead-acid for its simplicity and capital cost effectiveness.  As I believe is stated elsewhere on the Battery University website, lead-acid is still the lowest cost per kW energy storage solution. If you would like to discuss the general concept of battery-electric winches further, we can figure out how to take that off line. I am always open to other views on this topic and would welcome the dialog.

But the question remains, what can be done via charging strategies during prolonged stationary storage to extend the lifetime of flooded lead-acid battery systems?  My application is just an example of a scenario that might have broader applicability.

On August 7, 2013 at 10:54pm
Bevan Paynter wrote:

Stennis- correct charging & load usage, avoiding sulphation, clean connections. As to de-layering of the mixed electrolyte- this is a subject that is by no means settled or even agreed upon that it happens. My experiments have shown that over-charging up to 16v certainly stirs up sediment from bottom of cell/s- mainly fine lead particles- now, whether it is thought that these particles are helpful to rest of cell/s/batt is up to you & everyone else to judge- i don’t think so!. Also avoid commercial additives promised to prolong life of batt- don’t work! What does work is a teaspoonful of mag sulphate, alum sulphate, & dbla(chelator) to each cell- takes about month to work(load batt heavily then immed recharge couple times). Batt seems as if new- did about year ago- still good on several diff sli batts(important- disconn batt from all loads- like immobilisers etc).

On August 8, 2013 at 1:24pm
Stennis wrote:


Thank you for your thoughts.  My read is that keeping the battery fully charged and making sure the charge is saturated is the key to long term storage.

You indicate that commercial additives don’t work but then describe your own mix that you say does.  Is there some technical basis for the chemical mix you describe?  If this mix works, why does someone not make a commercial mix similar to what you recommend?  What makes you believe existing commercial mixes are not similar to what you have recommended?

On August 8, 2013 at 10:54pm
Bevan Paynter wrote:

Stennis- no doubt there may be or will be(now!) mixes similiar- what I have tried & don’t work are anything mainly cadmium sulphate. (The majority). The formulas I describe have been used for maybe 100 years!. No mix will work where the batt has faulty cells-s/c or o/c- but where a little sulphation is present . The biggest trick is removing batt from vehicle after every run & fully charging it( the average vehicle never fully charges a batt- or in the case of taxis eg, overcharges batt- leading to short life in both cases.) the only way to charge batt is at constant voltage of 14v watching ammeter- when charge rate falls to almost zero batt is fully charged(modern chargers with micro processor control do same).

On August 11, 2013 at 9:13am
Dalton Hanks wrote:

I bought a new Roadtrek Etrek at the cost of $135000!  This CS Etrek is supposed to run AC , fridge and microwave(when needed) for 9 hrs.  The unit only gets 4 hours with 11000 BTU AC and Fridge on continually here in Florida.  My battery array is 8 six volt batteries and also a 240 watt solar panel for extra charging.  It also has a dual alternator as one is used for the battery array at 3500 watts on idle and 5500 watts going down the road.  Is that right?  Should it only get 4 hours or less when not plugged in?  Thanks Dalton

On August 11, 2013 at 11:14pm
Bevan Paynter wrote:

Sounds as if you have(had?) more money than sense! Batts are the big downfall in any alternative energy system- you all have to get used to economising on energy use!(ain’t free- like ac power seemed to be!)

On August 29, 2013 at 3:35pm
julius,chrizostom wrote:

you have helped me.thanks

On September 14, 2013 at 5:38pm
John Fetter wrote:

Stennis - Add nothing except water. To keep lead-acid in good condition in long storage, keep the batteries cool and give them a brief charge once a week using a timer. Observe the voltage rise during charge and set the timer to switch off at about 2.55 volts per cell.

On September 14, 2013 at 10:30pm
Stennis wrote:


Thank you.  That is along the lines I was considering.  Your interval of 1 week and charge to 2.25 V per cell is the kind of quantitative information I was looking for.  Any guidance on what C rate or range to do this periodic recharge to?

On September 15, 2013 at 12:15am
John Fetter wrote:

Stennis - The ideal current is the equivalent of an equalizing charge, for example C/20. My recommended charge termination potential is 2.55V. You might find from observation a lower voltage will work but 2.25V is too low. If you can, use intervals of two weeks.

On September 15, 2013 at 12:52am
Stennis wrote:


Sorry, 2.25 was a typo - I meant 2.55.  So your C/20 scheme does not intentionally ‘boil’ the electrolyte to reduce acid stratification? 

Just to be clear, the extended storage will likely be over the winter in an unheated storage unit.  In my local, eastern Washington, the highs should rarely be over 50 F with overnight temperatures commonly well below freezing.  Would that push out your recommended interval.

On September 15, 2013 at 5:55am
John Fetter wrote:

Stennis - Changing an already charged battery continuously at C/20 causes it to gas briskly. Charging an already charged battery that has been standing a couple of weeks and stopping at 2.55 volts “will catch its attention” in terms of gassing, that’s all. I believe the electrolyte will definitely not stratify. This method will not use much water. Cold helps to conserve charge.

On September 15, 2013 at 10:12am
Stennis wrote:


Thank you very much for the information.  I think I have what I need now.

On October 8, 2013 at 7:16pm
Don wrote:

I have four six volt batteries in series in my1995 RV purchased summer of 2012. I left them in the RV last winter ( which was fairly mild). They are house batteries. I notice now that the separators at tops of the cells are getting flaky and presume that this is sulfation or stratification starting to take place .I am somewhat surprised as I have a 2000 watt inverter and it is supposed to keep the batteries charged and I always use distilled water when topping them up. Can you give me a heads up on what might be the problem.
Many thanks

On October 8, 2013 at 11:28pm
Bevan Paynter wrote:

Don- “house batt” means deep- cycle? Disconnect each batt from others- measure term volts with dmm- all about 6v4? Next put em 1x1 on fully automatic “smart ” batt charger- @ full charge leave for week- term volts still up? If not is a s/c cell/s. If all are say 6v4 put each 1 on a high rate discharge test to see amps each puts out- if all about same means all are ok. Seperator “buckling” is usually nothing to worry about(at top)- it happens in all batts!. What is really useful is an impedance tester for batts- they are expensive to buy, but can be made cheaply. The principle is reading the acv across terms while pulsing a load- taken when new & periodically after, it says exactly the amount of aging in batt.

On October 9, 2013 at 5:49am
Don wrote:

Just want to say thank you for sending me a reply to my inquiry. .I much appreciate
your taking time to get back to me so soon.

On November 23, 2013 at 12:47am
kanthiraj wrote:

Dear Bevan,

I am electrical engineer, past 12 years in battery testing field especially in VRLA and Auto motive .Now we have problem with Flat plate batteries for invertor application.  In 12V/150Ah,1.250 Filling gravityand testes @27°C.  Initially it delivers in 400W test for more than 3hrs . But after 20 cycles it come down to 1:30 hrs due to gravity impact in all cells after recharge of 24 Hrs in 14.40V it raises 1.150 only how to solve the issue???

On November 24, 2013 at 11:37pm
Bevan Paynter wrote:

You engineer- me self taught! I would use ammeter in series with your 14.4 v charge- batt only fully charged when amp rate drops to say o.2 A. If no fault in batt plate assbly(s/c plates) may be plates absorbing acid thereby dropping sg. If happy batt is fully charged as above, adjust sg to get 1.260 @ 25’C- then see what happens in further discharge/recharge cycles. no doubt you are using refractometer to check sg?.

On January 16, 2014 at 7:40pm
Tom wrote:

Golf cart batteries, four 12v in series -  48v. — the famous rotten egg sulfur aroma has come calling.  It only visits when operating the cart - not noticeable when charging or when cart is fully charged and at rest. (Only seems to stink of sulfur when I get underway. 

I added some distilled water before the odor became really obvious.
Can’t find any damage / crack in battery case.   

Should be obvious that I am new to deep cycle batteries and elec vehicles.  Thanks for any consultations . . . 

On January 16, 2014 at 11:23pm
John Fetter wrote:

Tom - The smell is most likely from stibine, a gas that is given off by golf-cart and forklift batteries when they are excessively overcharged. Probably collects somewhere in the vehicle at the end of the charge when the batteries are gassing, gets blown out when you start driving the vehicle. Stibine is a compound of hydrogen and antimony. It becomes poisonous if you can smell it but carry on breathing it in anyway.
The positive plate grids contain, in addition to lead, a metal called antimony. It is used to make the plates more durable. Batteries normally give off a mild “bubbly” stink when they are charged. Caused by parts per billion of stibine. (Harmless.) This intensifies when the batteries are overcharged. (Harmful.)
Batteries do not give off sulfur.

On March 8, 2014 at 9:42am
CLaire wrote:

My 4 x 12v-100Ah VRLA Gel batteries rigged up to run my solar powered house. It has been working weel for 4 years but now the 12v lights go out after only 1 hour after dark. The batteries are not holding their charge. Will adding distilled water to the batteries fix them?

On March 24, 2014 at 9:54am
Charles Martel wrote:

Solid mass of crystals at outside base of battery.
I put a 12V on a trickle charger (on a metal table top); some days later I see a mass of sugar like gray crystals along the entire base of the battery, an inch high and an inch deep (!)
What’s the cause ? I assume electrolysis has some how pulled material from the table.

On May 27, 2014 at 11:04am
stuart wrote:

hi i got a yuasa battery for my sinnis qm 125 i had it like 9 months ago i filled it with water and left over acid from the pack i had as it was completely empty the caps got black on them and now i checked my battery today and its completely empty again what could be the problem any suggestions

On June 8, 2014 at 8:03am
siva wrote:

tall tubular battery i filled distilled battery water the ups exceed low battery when using time

On June 10, 2014 at 5:06pm
Frank wrote:

Can charging the batterie with low water level permanently damage it? If yes, why?
Thank you

On June 10, 2014 at 11:51pm
John Fetter wrote:

Frank - Your battery will have a low electrolyte level, not a low water level. The portions of the plates and separators that are submerged will be in acid that is more concentrated than normal and might suffer damage. The portions of the plates that are above the electrolyte will dry out and the negatives will become discharged.
You must add purified water ASAP. Do not fill to the maximum level but slightly below. Then charge the battery slowly and for many days. If the battery still works the electrolyte levels will slowly rise, initially the voltage will remain low and after several days the voltage will rise to somewhere in the region of 15.5 volts and the battery will be gassing. The gassing will mix the electrolyte and the water. If the voltage rises quickly and does not fall, buy a new battery. 

On June 11, 2014 at 7:37pm
David wrote:

Bevan Paynter
What is dbla(chelator) you refer to please?

On June 30, 2014 at 8:31pm
Utkarsh wrote:

Is it o.k to use the water from an ac unit to fill the battery?

On June 30, 2014 at 11:12pm
John Fetter wrote:

Utkarsh - I have used ac water in batteries many times. There may be dust in an ac that is used intermittently, which could be a problem, and algae in one that is used all the time.
Algae is actually beneficial to batteries.
Ask ten battery experts and they will all tell you not to use water with algae. My research group did, in golf-cart batteries, deliberately, to see what would happen. The algae increased their cycling life by roughly 50%.

On July 3, 2014 at 12:40am
mohit waghela wrote:

Beven, would you please tell me what is the reason of water turning black into solar tubular battery ? Should i remove complete water from it and filled with new distilled water ??
provide the relevent solution for this problem

On July 4, 2014 at 8:07pm
atif wrote:

Hi floks I just wanted to ask that I just purchased a new 12 volt 175 amps flooded battery for my ups as agm batteries are not available here in pakistan it has been a month since I haven’t checked the battery today I checked the caps of the battery and I noticed black layer on the inside of all caps its not completely black but cloudy plz can u guy tell me if my battery is fine or what.

On July 4, 2014 at 11:29pm
John Fetter wrote:

atif - A flooded type is better. It can last about twice as long as AGM. The black stuff is harmless. It is predominantly carbon, mixed with other materials, that are put into the plates by the manufacturers. There may be some oil as well, from the separators. Traces of these materials are typically given off by the plates and separators during charging. These materials float on the acid electrolyte and the gassing from charging causes them to splash onto the caps. If I did NOT see this in a battery I would become worried.

On July 10, 2014 at 3:18pm
Josh G wrote:

What would happen if you used Chilled Water that has been treated with chemical from a closed loop instead city with was filtered? The wet cell battery is a duo cell battery.

On July 15, 2014 at 7:26am
RICK T wrote:

I believe that my batteries froze this past winter. When I put them on charge all batteries started expelling liquid in small quantities. Since then my battery capacity is dramatically reduced. what can I do.

On July 29, 2014 at 1:45am
tonykid wrote:

Question. As I open my solar battery the electrolyte is dried there is no sign of water. pls can I refill it with distilled water or with the acid water

On July 29, 2014 at 2:04am
John Fetter wrote:

tonykid - You can fill with distilled water. Then charge slowly for a long time. There is a high likelihood you will not be able to recover the batteries due to the low electrolyte, which causes plate damage.

On July 29, 2014 at 6:31am
tonykid wrote:

But sir I saw people taking there battery to refilling service center. and after it work fine

On July 29, 2014 at 7:35am
John Fetter wrote:

tonykid - I suggest you do the same thing.

On August 21, 2014 at 3:09am
sunil wrote:

any one can give a solution for our doubts, the battery voltage is 12 and the spgr is 1.250, when discharged the battery with 400 watts bulb, the back up is just 20 minutes.
the battery is just 2 yrs old

pls advice

On September 1, 2014 at 8:52am
Sarima wrote:

Hi, my battery’s capacity has drastically reduced after I added battery water. It’s perfomance has been half of that I used to get before adding water.
The battery was bought in August 2011.
What can I do to restore it??

On September 1, 2014 at 9:38am
John Fetter wrote:

Sarima - I suspect you may have allowed the electrolyte level to fall far enough to expose big areas at the top of the plates to the air. These areas will have become totally discharged and might be damaged. They are now taking all the charge and giving very little back. You must give the battery a very long, slow charge to attempt to restore these areas.

On September 9, 2014 at 9:42am
Royce wrote:

I have a golf cart with six 6 volt lead acid batteries, NOT maintenance-free. Five of them are over 3 years old, the sixth one was replaced this year. They are all boiling the liquid out and will not hold a charge long enough to power the cart. I think they are all toast, even the newest one. Am I correct? What might be the cause of this boiling?

On September 10, 2014 at 5:02am
Jeroen van Oosten wrote:

I’m having a weird problem with a battery where the electrolyte level keeps dropping.

It’s a small motorcycle battery, 14Ah, wet cell with caps to fill. It’s fairly new, 18 months old, but not used much (a ride every few weeks). I removed it from my motorcycle 2 months ago because it couldn’t start the engine. I noticed fluid level in two cells was way too low. So I topped it up with distilled water, gave it a quick charge and let it rest because I had other things to do.

Yesterday I was trying to charge it slowly, using a lab bench power supply. I first checked all the cells and noticed a few where the plates were not submerged (though still wet and above the minimum level), so I gave them a few drops of water and started charging. I set the voltage to precisely 2.30 V per cell, and it was charging with 0.63A for a few hours (less than C/20). I measured the voltage and amperage each hour and by the time I got to bed (7 hours later) the current had dropped slightly; the battery was producing some bubbles. I then disconnected the power supply. Everything looked okay.

But this morning, the fluid level in one cell had dropped considerably! The other cells are okay, just one cell is10% below the minimum level on the battery (I can’t rememember if it was one of the ‘dry’ cells when I removed the battery from my motorcycle). I did not top it up yesterday. Open circuit voltage of the battery was 12.20V.

- Is it normal for a battery to bubble, even at a low voltage and slow charge?
- What could cause the electrolyt level to drop considerably, even after the charger is disconnected?
- Do you think this battery is still salvagable?


On September 11, 2014 at 12:13am
John Fetter wrote:

Royce - Your batteries are being overcharged. Something is wrong with your charger.

Jeroen - 1. The rapidly falling electrolyte levels indicate over charging. The voltage readings indicate undercharging. One of these is not correct. You are in the best position to check.  OR
          2. An impurity has somehow been put into your battery electrolyte that is causing an increase in the rate of self discharge.

On September 17, 2014 at 11:29am
Jeroen van Oosten wrote:

John - Thanks for your answer. It is indeed very weird, the battery shows signs of both over- and undercharge. I am also inclining towards an impurity or other manufacturing problem. Either way, this battery is toast.

On September 18, 2014 at 5:10am
Shekhar Rastogi wrote:

Dear Sir,
I purchased a lead acid tubular battery 150 ah for my domestic UPS (900 VA). I found the fully charged battery as my UPS showed operated 150 watt load just for 3 hours. But as per calculation the battery should have worked for at least 8 hours with this load. I called the technician and he told the specific gravity was low just 1.150 and that a specific charger may be used to increase sg. The battery is only two months old. My first question—-What back up time should I expect from the battery for 200 watts load and second question—-Would the sg of the battery would remain normal after being charged by the charger as stated by the technician?

On September 19, 2014 at 10:10pm
Shahrukh sheikh wrote:

My ups charges the battery @ of 30A12v. The battery is lead acid nonsealed battery of 100A. Now the problem is this that the charge of battery continuously decreases when the ups stops after full charging. Then ups again starts charging the battery without any usage. Please can you help me what should I do in this situation.

On September 20, 2014 at 12:32am
John Fetter wrote:

Shekhar - A battery in the situation you describe, with an SG of 1.150, is for all intents and purposes fully discharged and needs to be charged. It is possible your charger is not working properly.

Shahrukh - A lead-acid battery that is first fully charged, then simply left standing, will discharge slowly, on its own. This can take six months, a year. The UPS will try to counter this by occasionally giving the battery a brief charge. You have not provided information about the time or current when the UPS starts again. I have given you an interpretation. If I owned a UPS and it did not do this, I would get worried - not the other way around.

On September 20, 2014 at 1:38am
Shekhar Rastogi wrote:

Thanx a lot, John. You are right, the battery was fully discharged. It worked for very little time. Eventually, the dealer has changed the battery. He has given me a new one on its place. It is working good.
Thanx once more.

On November 1, 2014 at 2:32pm
frank wrote:

Wow, a lot of confusion and stuff ups here. 

40 years ago our fathers knew how to maintain the simple lead acid batteries in their cars but the actual charging mechanism was in the car alternator and fixed.  No one played with any other systems like we do today, it was simple. 

Today many people want to take batteries out of their native devices and tinker with them, build their own electronic systems basically.  But unless you have spent many many hours researching and setting up your charging system, do not expect anything but failure.

Batteries are complex electro-chemical devices, they are not like a bucket you simply fill with water.  Voltages and currents and time periods must be kept within specific boundries or you will destroy these sensitive devices.  AGM and gel cells only complicate the issue.  So either get a professional to set it up for you of do your homework, lots of it!

On November 2, 2014 at 6:26am
John Fetter wrote:

frank - I believe you are right about batteries being complex electrochemical devices. Batteries made from the purest lead that has been processed into high quality positive and high quality negative plates, the purest acid and provided with the purest refill water throughout their service do not last very long. Add the right impurities in exactly the right concentration and they just go on and on working. Can you suggest why?

On November 12, 2014 at 6:07pm
Conrad wrote:

about lead -acid batteries.  In golf carts: some 36 volt with 6- six volt batteries; some 48 volt with six 8 volt batteries, or 4- eight volt batteries.. In all cases this battery of batteries are charged overnight with a single charger.  I would like to charge my trolling motor and boat batteries with a single battery charger…in my basement for overwinter storage.  Can this be done with a simple parallel wire hookup (using 6 ga. stranded wire)? ...or are diodes et al. necessary in the wiring scheme?
    Also, regarding older (6-7 yrs old), deep-cycle batteries and restoration efforts.  Years ago, someone told me , and I never tried it, that adding an aspirin to each cell, would aid in rejuvenating the battery cells. I may have been gotcha’d…but has anyone tried this remedy with any positive results

On November 16, 2014 at 3:20am
Ashwajeet Singh wrote:

When i opened my bike’s battery after two years ( it seemed dischard all the time) i found the electrolyte was solid at the bottom i topped the battery with distilled water from a closed container but i still gave performance as before. What to do?

On January 1, 2015 at 10:15pm
keith wrote:

Strange one…
The battery is a 232 amp hr deep cycle (6 volt) and it has been doing an odd thing.

I check the electrolyte at the end of a charge/absorb cycle and one cells volume is low, the other is almost over flowing. I even out the electrolyte among the cells. It charges during the next day. I check the electrolyte and one is really low and the other is over flowing.
Is it possible for one cell to be “leaking” into the other?


On January 3, 2015 at 5:48am
ashish wrote:

Hi,after changing battery water my inverter is not charging the battery.what should I do now.plz help

On February 6, 2015 at 9:42am
Larry wrote:

I just recently installed an off grid Solar Array. Wanting to keep my batteries in the 20% DOD range I determined that I would apply a charging system external to the solar charging during a few night hours.  At first I was just waiting until the voltage on the system dropped to 80%. But then it dawned on me that if the chemical action created by charging leads to shorter battery life, then I might be doing harm or shortening the life of the batteries by applying charge only after discharge as opposed to applying the charger to maintain a charged state until a a few hours after dark. So now I have the secondary charger take over right at sunset and maintain the charge latter into the night. This creates only on chemical reversal per 24 hours instead of two. Does this seem like sound reasoning?

On February 22, 2015 at 2:53am
Edward P wrote:

Interesting in this discussion that no one has mentioned Peukert’s Exponent in their solar grid calculations. This is why batteries do not last as long under load as you would think.

On February 22, 2015 at 5:13am
John Fetter wrote:

Edward - Everyone knows the higher the current draw, the lower the available ampere-hours. Perhaps not everyone knows this by its formal name, Peukert’s Exponent.
Peukert predicts battery performance under ideal conditions. Batteries in real life tend to deviate from this ideal for many reasons. This is what people are attempting to discuss on these pages.

On March 26, 2015 at 11:41pm
Steve wrote:

My 12v battery I use for my boat is pushing out water out the terminals after I put it on a new 5amp trickle charger I just bought for about four hours and also topped up the water levels before charging as they were low. For the past three days water is slowly coming out one or two terminals that is actually closed. What caused this to happen and how can I fix this problem? Your advise is much appreciated.